Multi-cloud active mesh network system and method

ABSTRACT

According to one embodiment, a network system features a first virtual private cloud (VPC) network and a second VPC network. The first VPC network includes a first plurality of gateways. Each gateway of the first plurality of gateways is in communications with other gateways. Similarly, a second VPC network includes a second plurality of gateways. Each of the second plurality of gateways is communicatively coupled to the each of the first plurality of gateways to support data exchanges between resources deployed in different public cloud networks.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 17/862,110 filed Jul. 11, 2022, which is a continuation of U.S. patent application Ser. No. 17/186,911 filed Feb. 26, 2021, now U.S. Pat. No. 11,388,227, filed Jul. 12, 2022, which is a continuation-in-part of U.S. patent application Ser. No. 17/186,911, which is a continuation-in-part of U.S. patent application Ser. No. 17/079,399 filed Oct. 23, 2020, which claims the benefit of priority on U.S. Provisional Patent Application No. 62/982,679 filed Feb. 27, 2020, the entire contents of all of which are incorporated by reference herein.

TECHNICAL FIELD

Embodiments of the disclosure relate to the field of networking. More specifically, one embodiment of the disclosure relates to a load-balanced, full-mesh network architecture configured to mitigate communication disruptions, especially between virtual private clouds (VPCs) within different public cloud networks.

GENERAL BACKGROUND

Over the past few years, cloud computing has provided an Infrastructure as a Service (IaaS), where resources are provided as part of a cloud computing platform (e.g., public cloud network) and made accessible to tenants as a service. One of these services allows tenants to run software components (e.g., virtual machines instances such as virtual servers) residing within the cloud computing platform. Hence, the migration of software functionality into cloud computing platforms has led to greater usage of virtual private cloud networks (VPCs).

A virtual private cloud network (VPC) is an on-demand, configurable pool of shared resources, which are allocated within the cloud computing platform and provide a certain level of isolation between the different organizations or other entities (hereinafter, “users”) using the resources. The isolation between one VPC user from other users of the same cloud computing platform may be achieved through allocation of a private Internet Protocol (IP) subnet and a virtual communication construct (e.g., virtual local area network “VLAN” or other protected communications) per user. For example, Amazon® Web Services (AWS®) provides for the purchase of Amazon® Elastic Compute Cloud (EC2) services with dedicated data processing capabilities for a particular user.

Currently, certain cloud computing platforms provide connectivity between VPCs. This connectivity, sometimes referred to as “peering,” constitutes an establishment of peer-to-peer communications between separate VPCs for the purpose of routing data traffic as requested. These peer-to-peer communications include a primary communication link and a high availability (HA) communication link. The HA communication link is operational in response to a “failover” condition. More specifically, the communications between a gateway deployed within a VPC and either (i) a gateway of another VPC or (ii) an on-premises computing device such as a router controlling communications within an on-premises network are accomplished by the primary communication link placed in an “active” state. The HA communication link is initially set to a “standby” (inactive) state, but is switched to an “active” state when the primary communication link fails. However, this VPC “failover” communication scheme suffers from a number of disadvantages.

One disadvantage associated with the conventional VPC failover communication scheme is that it requires deployment of complex failover logic within the controller to manage operability of the public cloud network. For example, the failover logic would need to continuously track the current state of the primary communication link and would need to conduct an update of a gateway routing table for the cloud computing network in response to failure of the primary communication link. Additionally, in response to failure of both the primary and HA communication links, the failover logic would need to reprogram the VPC routing table. The VPC routing table is relied upon for determining which gateway is targeted to receive downloaded data while the gateway routing table is relied upon for determining which communication link is used for transmission of the downloaded data. Another disadvantage with the active-standby failover scheme is the inefficient use of resources allocated for the standby communication link. These resources are never used until a failover event happens.

The updating of both of these routing tables is time consuming and disruptive to ongoing communications, especially the reprogramming of the VPC routing table. The convergence (stabilization) of the network and avoidance of disruption of data communications within or to the public cloud is necessary as more companies migrate their networking operations to the cloud.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which:

FIG. 1 is a diagram of an exemplary embodiment of a public cloud computing platform implemented as a load-balanced, full-mesh network featuring multiple virtual private cloud networks that collectively support communications between multiple instances within a private cloud network and an on-premises network;

FIGS. 2A-2B are exemplary embodiments of a gateway routing table programmed to represent IPSec tunnel supported by a gateway of a first virtual private cloud network of the load-balanced, full-mesh network.

FIGS. 2C-2D are exemplary embodiments of a transit gateway routing table programmed to represent IPSec tunnel supported by a transit gateway of a second virtual private cloud network of the load-balanced, full-mesh network.

FIG. 3 is an exemplary illustration of a logical representation of a gateway deployed within the virtual private cloud network of FIG. 1 .

FIG. 4 is a second exemplary embodiment of a multi-public cloud computing platform, including the full-mesh network configured to mitigate the disruption of communications between four (4) virtual private cloud networks that are deployed within two or more public cloud networks.

FIG. 5 is a flowchart of an exemplary embodiment of the operability of the public cloud computing platform of FIG. 1 in supporting communications between multiple virtual private cloud networks without reliance of changes to the VPC routing table.

FIG. 6A is a diagram of an exemplary embodiment of the public cloud computing platform supporting communications between multiple virtual private cloud networks over a first communication link (IPSec tunnel) in response to failure of a second communication link (IPSec tunnel) formerly utilized by the virtual private cloud networks.

FIG. 6B is a diagram of an exemplary embodiment of the public cloud computing platform of FIG. 6A supporting communications between multiple virtual cloud networks over the second communication link in response to failure of the first communication link.

FIG. 6C is a diagram of an exemplary embodiment of the public cloud computing platform of FIG. 6A supporting communications between multiple virtual private cloud networks over a secondary tunnel in response to failure of the first and second communication links.

DETAILED DESCRIPTION

Embodiments of a system and method for establishing a load-balanced, full-mesh network over multiple public cloud networks, where the full-mesh network mitigates disruption of communications directed to or from virtual private cloud networks (VPCs) due to communication link failures. The full-mesh network may be accomplished by establishing (i) a first cloud-based networking infrastructure operating as a first virtual private cloud network (hereinafter, “spoke VPC”) and (ii) a second cloud-based networking infrastructure operating as a second virtual private cloud network (hereinafter, “transit VPC”). These transit VPCs may be deployed within different public cloud networks, where transit VPCs deployed with Microsoft® Azure® are sometimes referred to as virtual networks or “VNets”.

The spoke VPC includes a set of (e.g., two or more) gateways (hereinafter, “spoke gateways”), which are communicatively coupled to one or more instances (e.g., cloud instances associated with a particular subnet or particular subnets as described below) and a set of gateways deployed within the transit VPC (hereinafter, “transit gateways”). Each of the spoke gateways and transit gateways may be accessed in accordance with a unique Classless Inter-Domain Routing (CIDR) routing address to propagate messages over the network.

Besides communicatively coupled to the set of spoke gateways, the set of transit gateways may be communicatively coupled to one or more computing devices deployed within an on-premises network (hereinafter, “on-prem computing devices”). Herein, the transit VPC may be configured to be deployed within the same public cloud network as the set of spoke gateways or may be deployed in a different public cloud network. The transit VPC is configured to control the propagation of data traffic between the spoke VPC and the on-premises network while the spoke VPC is configured to control the propagation of data traffic between instances maintained within the spoke VPC and the transit VPC.

According to one embodiment of the disclosure, the first cloud-based networking infrastructure features a one-to-many communication link deployment (e.g., criss-cross peering), where each spoke gateway supports multiple, active peer-to-peer communication links to different transit gateways and each transit gateway supports multiple, active peer-to-peer communication links to different spoke gateways as well as an active peer-to-peer communication link to each on-prem computing device. According to one embodiment of the disclosure, the peer-to-peer communication links may constitute cryptographically secure tunnels, such as tunnels operating in accordance with a secure network protocol. One example of a secure network protocol may include, but is not limited or restricted to Internet Protocol Security (IPSec). Hence, for clarity sake, these peer-to-peer communication links may be referred to as “IPSec tunnels.”

Herein, the deployment of full-mesh peering in lieu of primary/HA communication links utilized in conventional cloud computing platforms provides a number of technological advantages. For example, the full-mesh peering architecture is configured to avoid intensive monitoring of routing tables relied upon by a gateway (referred to as a “gateway routing table”) for determining which IPSec tunnel is used in the transmission of data, especially for a tunnel state change. To achieve load-balancing, all of the IPSec tunnels directed to the transit gateways are set to identical, equal cost multi-path (ECMP) routing parameters, namely identical routing weights and ECMP metrics as described below. Alternatively, according to another embodiment of the disclosure, loading balancing is not based on ECMP; rather, load balancing is achieved through an assignment of weights such that different tunnels may be assigned with different weights, based on one or a combination of factors such as bandwidth, preference, or the like.

Herein, when an IPSec tunnel fails, the gateway updates its gateway routing table autonomously by disabling (bring down) a tunnel interface (e.g., virtual tunnel interface) corresponding to the failed IPSec tunnel without reliance on activity by a controller that manages operability of the full-mesh network. As a result, the gateway precludes messages from being routed through the failed IPSec tunnel to mitigate data transmission loss. Instead, the messages are routed through a selected active IPSec tunnel, which may be reassigned to communication with all or some of the instances within a particular instance subnet. In response to the IPSec tunnel becoming operational (i.e., the IPSec tunnel goes up), the gateway will bring up the corresponding tunnel interface and recover the routing path if removed from the gateway routing table (e.g., routing path removed when all of the IPSec tunnels to a particular destination becoming disabled).

Additionally, the full-mesh network provides another technological advantage by avoiding time intensive reprogramming of a virtual private cloud (VPC) routing table relied upon for determining a routing path between an identified source and destination. This may be accomplished by establishing one or more secondary tunnels for each routing path, where the secondary tunnel provides an alternative routing path via a gateway residing within the same VPC (e.g., gateways within the spoke VPC, gateways within the transit VPC, etc.). Each secondary tunnel supports the transmission of data through the alternative routing path when all of the IPSEC tunnels from a particular gateway have failed. Hence, secondary tunnels enable another gateway to operate as an intermediary device to support continued communications from the particular gateway with a remote peer destination (e.g., cloud instance, on-prem computing device, etc.). Each of the secondary tunnels may be configured in accordance with Generic Routing Encapsulation (GRE) tunnel protocol to secure communications between gateways within the same VPC. However, it is contemplated that another tunneling protocol, such as any IP routable tunnel based on Private IP addressing, inclusive of IPSec, may be used other than GRE.

Routing path selection via the gateways within the VPCs may be accomplished through an equal cost multi-path (ECMP) routing strategy, namely next-hop message forwarding to a single destination can occur over multiple “best” paths that are determined in accordance with an assigned ECMP metric. Hence, the IPSec tunnels associated with a gateway (e.g., spoke gateway or transit gateway) are assigned equivalent ECMP metrics that are lower than the ECMP metrics assigned to any of the secondary (GRE) tunnels.

Besides the network architecture per se, the operability (method) performed by the system for establishing the load-balanced, full-mesh network to mitigate disruption of communications directed to or from the VPCs is described. Herein, a controller managing operability of one or more public cloud networks configures one or more spoke VPCs by segregating cloud instances within each spoke VPC to particular subnets. A “subnet” is a segment of a VPC's IP address range designated to group resources (e.g., managed software instances each directed to particular functionality) based on security and operational needs. Hence, each instance subnet established within a spoke VPC may be a collection of instances for that spoke VPC that are selected to communicate with a selected spoke gateway residing in the spoke VPC.

Thereafter, the controller may be configured to collect VPC information (e.g., VPC subnet allocations, VPC routing tables and their association with subnets) and/or configure a VPC routing table associated with each spoke gateway to establish communication links (e.g., logical connections) between a certain spoke gateway and cloud instances associated with a particular instance subnet. The VPC routing table is programmed to support communication links between different sources and destinations, such as an on-prem computing devices, a cloud instance within a particular instance subnet or the like.

Besides the VPC routing tables for each of the spoke gateways, the controller may be adapted to configure gateway routing tables for each of the gateways within the VPCs of the full-mesh network. More specifically, according to one embodiment of the disclosure, the controller may be configured to initially program gateway routing tables for both spoke gateways residing within the spoke VPC(s) and transit gateways residing within the transit VPC(s). The gateway routing tables are relied upon by the gateways for determining which tunnels to use for propagating data traffic (e.g., messages) towards a destination (e.g., virtual tunnel interface for a destination cloud instance or computing device). For this embodiment of the disclosure, the gateway routing tables includes both IPSec tunnels and secondary (e.g., GRE) tunnels between gateways within the same VPC to be used in the event that all of the IPSec tunnels have failed.

The gateway routing tables are accessible to their corresponding gateways, and are updated by these gateways. For example, in response to a failed IPSec tunnel (e.g., change in tunnel state), the gateway associated with the failed IPSec tunnel disables its virtual tunnel interface (VTI). By disabling the VTI associated with the failed IPSec tunnel, further data transmissions over the failed IPSec tunnel is prevented. The disabling of the VTI may be conducted by a gateway (e.g., spoke gateway or transit gateway) without further operability by the controller.

Logic within the gateway detects reversion in the tunnel state (e.g., IPSec tunnel is now active) and, if so, the gateway re-activates the tunnel interface (e.g., remove “disabled” tag and/or resets “active” tag) or recovers the routing path associated with the previously failed IPSec tunnel if removed from the gateway routing table. This recovery of the routing path may be accomplished by accessing a data store (e.g., database) associated with the gateway that maintains routing paths available to that gateway, even failed (disabled) IPSec tunnels.

Based on the foregoing, the reduction in VPC routing table programming is made available through the configuration of the secondary (e.g., GRE) tunnels. End to end load balance is achieved through the network architecture by using of two technics at different stages. Firstly, from VPC instances to spoke gateway, each VPC instance is under a routing subnet. The subnet is associated with a routing table. The routing table route forward data traffic from the instance to a spoke gateway. Traffic from difference source instances of different subnet (routing table) are sent to different spoke gateways, instead of all source instances sending traffic to one spoke gateway in active-standby scheme. Secondly, between spoke gateway and transit gateway, or transit gateway to on-premises routers, this may be based on analytics conducted on a 5-tuple of a message (e.g., source IP address; source port; destination IP address; destination port; destination protocol), which is routed from between the spoke gateway and transit gateway or between the transit gateway and on-premises routes. The analytics may be a one-way hash operation in which the results (or a portion of the results) are used to select a particular ECMP link in the routing table to transmit of the data traffic.

Further details of the logic associated with one embodiment of the load-balanced, full-mesh network system architecture are described below:

Instance Subnets: Multiple instance subnets may be generated in a spoke VPC so that instances forming a particular instance subnet are forwarded to a selected spoke gateway.

VPC routing table(s): A VPC routing table may be used to associate spoke gateways within each VPC with one or more different instance subnets. Load balancing is achieved by implementing the full-mesh network system, where identical, equal cost multi-path (ECMP) routing parameters are assigned to each of the gateways and a secondary tunnel is established between each peer gateway pair within the same VPC. Therefore, the VPC routable table requires no programming unless the gateway becomes disabled (i.e., goes down), where the VPC routing table may be remapped based on the results of a 5-tuple analytics mapped to the remainder of the active gateways within the VPC.

Gateways: Multiple gateways are deployed in a VPC, where each gateway is logic that is configured to control the flow of data traffic from instances of the VPC to one or more remote sites or cloud networks along with traffic from/to computing devices within on-premises networks that may process data received from the instances. Having similar architectures, the gateways may be identified differently based on their location/operability within a public cloud network platform. The “spoke” gateways are configured to interact with targeted instances while “transit” gateways are configured to further assist in the propagation of data traffic (e.g., one or more messages) directed to a spoke gateway within a spoke VPC or a computing device within the on-premises network.

IPSec tunnels: Secure peer-to-peer communication links established between gateways of neighboring VPCs or between gateways of a VPC and a router of an on-premises network. The peer-to-peer communication links are secured through a secure network protocol suite referred to as “Internet Protocol Security” (IPSec). With respect to the full-mesh network deployment, as an illustrative example, where a spoke VPC has “M” gateways and a neighboring (transit) VPC has N gateways, M×N IPSec tunnels are created between the spoke VPC and the transit VPC to form the full-mesh network. These IPSec tunnels are represented in gateways by virtual tunnel interface (VTI) and the tunnel states are represented by VTI states.

Gateway routing: In gateway routing table, routing paths between the gateway and an IP addressable destination to which the tunnel terminates (e.g., another gateway, on-prem computing device, etc.), identified by a virtual tunnel interface (VTI) for example, are programmed with ECMP routing parameters, namely identical routing weights and ECMP metrics. Given consistent ECMP metrics are assigned to the IPSec tunnels, the selected routing path towards the remote network may be based on analytics conducted on certain information associated with data traffic (e.g., 5-tuple). These analytics may include conducting a one-way hash operation on the 5-tuple information where a portion of the hash value may be used to identify the selected IPSec tunnel. If any of the IPSec tunnels state is changed or disabled (or re-activated), the corresponding VTI may be removed (or added) from consideration as to termination points for the selected routing path.

Secondary tunnels: Each of the gateways in the same VPC may be configured to create secondary (backup) communication links (e.g., GRE tunnels) towards all other gateways within that VPC, also represented by VTIs. For example, with respect to a VPC including M gateways, each gateway will have M−1 secondary communication links. Herein, these secondary communication links are assigned with higher metric values within the gateway routing table than communication links (e.g., IPSec tunnels) pointing to a remote peer gateway. Therefore, according to one embodiment of the disclosure, a secondary communication link (e.g., GRE tunnel) will not forward traffic until all of the IPSec tunnels for that particular gateway have become disabled (gone down).

I. Terminology

In the following description, certain terminology is used to describe features of the invention. In certain situations, the terms “logic” and “computing device” is representative of hardware, software or a combination thereof, which is configured to perform one or more functions. As hardware, the logic (or device) may include circuitry having data processing or storage functionality. Examples of such circuitry may include, but are not limited or restricted to a microprocessor, one or more processor cores, a programmable gate array, a microcontroller, an application specific integrated circuit, wireless receiver, transmitter and/or transceiver circuitry, semiconductor memory, or combinatorial logic.

Alternatively, or in combination with the hardware circuitry described above, the logic (or computing device) may be software in the form of one or more software modules. The software module(s) may include an executable application, an application programming interface (API), a subroutine, a function, a procedure, an applet, a servlet, a routine, source code, a shared library/dynamic load library, or one or more instructions. The software module(s) may be stored in any type of a suitable non-transitory storage medium, or transitory storage medium (e.g., electrical, optical, acoustical or other form of propagated signals such as carrier waves, infrared signals, or digital signals). Examples of non-transitory storage medium may include, but are not limited or restricted to a programmable circuit; a semiconductor memory; non-persistent storage such as volatile memory (e.g., any type of random access memory “RAM”); persistent storage such as non-volatile memory (e.g., read-only memory “ROM”, power-backed RAM, flash memory, phase-change memory, etc.), a solid-state drive, hard disk drive, an optical disc drive, or a portable memory device. As software, the logic may operate as firmware stored in persistent storage.

The term “computerized” generally represents that any corresponding operations are conducted by hardware in combination with software.

The term “gateway” may be construed as a virtual or physical logic. For instance, as an illustrative example, the gateway may correspond to virtual logic in the form of a software component that perform routing of data. As an illustrative example, the gateway may constitute a virtual machine (VM)-based data routing component that is assigned a Private IP address within an IP address range associated with a VPC including the gateway. As another illustrative embodiment, the gateway may constitute a virtual network (VNet). The gateway allows Cloud Service Providers (CSPs) and enterprises to enable datacenter and cloud network traffic routing between virtual and physical networks, including a public network (e.g., Internet). Alternatively, in some embodiments, the gateway may correspond to physical logic, such as an electronic device that is communicatively coupled to the network and assigned the hardware (MAC) address and IP address.

The term “cloud-based networking infrastructure” generally refers to a combination of software instances generated based on execution of certain software by hardware associated with the public cloud network. Each software instance may constitute a virtual network resource associated with the public cloud network, such as a switch, server or the like.

The term “message” generally refers to information in a prescribed format and transmitted in accordance with a suitable delivery protocol. Hence, each message may be in the form of one or more packets, frames, or any other series of bits having the prescribed format.

The term “transmission medium” may be construed as a physical or logical communication path between two or more electronic devices. For instance, as a physical communication path, wired and/or wireless interconnects in the form of electrical wiring, optical fiber, cable, bus trace, or a wireless channel using infrared, radio frequency (RF), may be used.

Finally, the terms “or” and “and/or” as used herein are to be interpreted as inclusive or meaning any one or any combination. As an example, “A, B or C” or “A, B and/or C” mean “any of the following: A; B; C; A and B; A and C; B and C; A, B and C.” An exception to this definition will occur only when a combination of elements, functions, steps or acts are in some way inherently mutually exclusive.

As this invention is susceptible to embodiments of many different forms, it is intended that the present disclosure is to be considered as an example of the principles of the invention and not intended to limit the invention to the specific embodiments shown and described.

II. General System Architecture

Referring to FIG. 1 , a first exemplary embodiment of a multi-cloud computing platform 100 implemented with a load-balanced, full-mesh network 110, which supports reliable communications between one or more instances of a virtual private cloud network (VPC) and one or more computing devices 180 deployed within an on-premises network 190, is shown. According to this embodiment of the disclosure, the full-mesh network 110 is configured to mitigate the disruption of communications between at least a first virtual private cloud network (hereinafter, “spoke VPC”) 120 and a second virtual public cloud network (hereinafter, “transit VPC”) 130 within the multi-cloud computing platform 100 due to communication link failures. Although two VPCs 120 and 130 are illustrated in FIG. 1 for clarity sake, it is contemplated that multiple “spoke” VPCs and multiple “transit” VPCs may formulate the construct of the full-mesh network 110 as shown in FIG. 4 . Also, the VPCs 120 and 130 may be deployed within the same public cloud network or different public cloud networks.

As shown, the spoke VPC 120 is configured with multiple VPC subnetworks 145 (hereinafter, “subnets”), where each of these subnets 145 includes different cloud instances. Each of the instance subnets 145 ₁ . . . , or 145 _(P) (P≥2) is configured, in accordance with a VPC routing table 150, to exchange data traffic with a selected gateway of a set of (e.g., two or more) gateways 125 ₁-125 _(M) (M≥2) maintained in the spoke VPC 120. Herein, these gateways 125 ₁-125 _(M) are referred to as “spoke gateways” 125 ₁-125 _(M). More specifically, a controller 160 for the full-mesh network 110 is configured to manage communication links between the instance subnets 145 ₁-145 _(P) and the set of spoke gateways 125 ₁-125 _(M) as represented by the VPC routing table 150, which is initially programmed to identify which spoke gateway 125 ₁ . . . or 125 _(M) is responsible for interacting with one or more instance subnets 145 ₁ . . . , or 145 _(P) (e.g., to receive message(s), forward message(s), etc.).

Referring still to FIG. 1 , according to one embodiment of the disclosure, the full-mesh network 110 may be accomplished by peering the set of spoke gateways 125 ₁-125 _(M) deployed within the spoke VPC 120 to a set of gateways 135 ₁-135 _(N) deployed within the transit VPC 130, which may be referred to as “transit gateways” 135 ₁-135 _(N) (N≥2). As ease of illustration, the set of spoke gateways 125 ₁-125 _(M) is represented as a first spoke gateway 125 ₁ and a second spoke gateway 1252, although three or more spoke gateways may be deployed within the spoke VPC 120. Similarly, the set of transit gateways 135 ₁-135 _(N) is represented by a first transit gateway 135 ₁ and a second transit gateway 135 ₂, although three or more transit gateways may be deployed within the transit VPC 130.

The spoke gateways 125 ₁-125 _(M) are configured for communications with transit gateways 135 ₁-135 _(N) via peer-to-peer communication links 127 ₁₁-127 _(MN). In particular, each spoke gateway 125 _(i) (1≤i≤M) is communicatively coupled to each of the transit gateways 135 ₁-135 _(N) via multiple, active peer-to-peer communication links 127 _(i1)-127 _(iN). Similarly, each transit gateway 135 _(j) (1≤j≤N) is communicatively coupled to each of the spoke gateways 125 ₁-125 _(M) via multiple, active peer-to-peer communication links 127 _(Ij)-127 _(Mj). The peer-to-peer communication links 127 ₁₁-127 _(MN) may constitute cryptographically secure tunnels, such as tunnels operating in accordance with a secure network protocol. One example of a secure network protocol may include, but is not limited or restricted to Internet Protocol Security (IPSec). Hence, the VPC-to-VPC tunnels may be referred to as “IPSec tunnels.”

In general terms, for the full-mesh network 110 that features the spoke VPC 120 including “M” spoke gateways and the neighboring transit VPC 130 including “N” transit gateways, M×N IPSec tunnels 127 ₁₁-127_(MN) are created between the spoke VPC 120 and the transit VPC 130. The IPSec tunnels 127 ₁₁-127_(MN) may be established and maintained through gateway routing tables 170 ₁-170 _(M) dedicated to each of the spoke gateways 125 ₁-125 _(M), respectively. For example, a first gateway routing table 170 ₁ determines which IPSec tunnel 127 ₁₁-127 _(1N) for use in forwarding a message from one of the cloud instances 140 assigned to the first gateway 125 ₁ to a destination instance (not shown) reachable via one of the on-prem computing device(s) 180.

As an illustrative example, as shown specifically in FIG. 1 , the first spoke gateway 125 ₁ is communicatively coupled to both the first transit gateway 135 ₁ via IPSec tunnel 127 ₁₁ and the second transit gateway 135 ₂ via IPSec tunnel 127 ₁₂. Similarly, the second spoke gateway 125 ₂ is communicatively coupled to both the first transit gateway 135 ₁ via IP Sec tunnel 127 ₂₁ and the second transit gateway 135 ₂ via IPSec tunnel 127 ₂₂. For this architecture, each spoke gateway 125 ₁ and 125 ₂ is communicatively coupled to each of the transit gateways 135 ₁ and 135 ₂ via multiple, active peer-to-peer communication links 127 ₁₁, 127 ₁₂, 127 ₂₁ and 127 ₂₂. The management of the IPSec tunnels 127 ₁₁-127 ₁₂ and 127 ₂₁-127 ₂₂ may be accomplished through gateway routing tables 170 ₁-170 ₂ and 175 ₁-175 ₂ maintained by each of the respective gateways 125 ₁-125 ₂ and 135 ₁-135 ₂, as described below.

Referring now to FIGS. 2A-2B, an exemplary embodiment of a portion of the first spoke gateway routing table 170 ₁ programmed to represent IPSec tunnels 127 ₁₁-127 ₁₂ supported by the first spoke gateway 170 ₁ of the spoke VPC 120 is shown. Herein, each IPSec tunnel 127 ₁₁ or 127 ₁₂ may be represented by a corresponding virtual tunnel interface (VTI) 2001 or 2002 and a state of each IPSec tunnel 127 ₁₁ or 127 ₁₂ may be represented by a corresponding virtual tunnel interface (VTI) state 210 ₁ or 210 ₂, respectively. No identification of link status (e.g., “linkdown”) identifies that the link is active. Selection of the IPSec tunnel 127 ₁₁-127 ₁₂ to support communications from the first spoke gateway 125 ₁ toward the on-premises network 190 may be accomplished through ECMP routing. As a result, each IPSec tunnel 127 ₁₁-127 ₁₂, selected to support message transmissions from the first spoke gateway 120 ₁, is assigned an equal ECMP metric (metric=0) 220, which is less than the ECMP metric 230 (metric=200) assigned to the secondary (GRE) tunnels (e.g., GRE tunnel 1291). It is contemplated that, while the IPSec tunnels 127 ₁₁-127 ₁₂ may be assigned identical ECMP metrics (metric=0) for load balancing, the GRE tunnel(s) may be assigned different ECMP metrics to prioritize the GRE tunnels from the first spoke gateway 120 ₁ upon failure of IPSec tunnel 127 ₁₁-127 ₁₂ shown in FIG. 1 .

Referring back to FIG. 1 , each transit gateway 135 _(j) (1≤j≤N) supports multiple active peer-to-peer communication links with each of the on-prem computing device(s) 180 (e.g., on-prem computing devices 180 ₁ and 180 ₂). Hence, where the transit VPC 130 includes “N” transit gateways in communications with a plurality of on-prem computing devices 180 ₁ and 180 ₂, N×2 IPSec tunnels 137 ₁₁-137 ₁₂ . . . and 137 _(N1)-137 _(N2) are created between the transit VPC 130 and the on-premises network 190. Similarly, the IPSec tunnels 137 ₁₁-137 _(N2) may be established and maintained through transit gateway routing tables 175 ₁-175 _(N) dedicated to each of the transit gateways 135 ₁-135 _(N), respectively.

As an illustrative example, a first transit gateway routing table 175 ₁ determines which IPSec tunnel 137 ₁₁-137 ₁₂ for use in forwarding a message received from the spoke VPC 120 and directed to the destination instance reachable via one of the on-prem computing devices 180 ₁ and 180 ₂. As shown in FIGS. 2C-2D, the first transit gateway routing table 175 ₁ may be programmed to represent each IPSec tunnel 137 ₁₁-137 ₁₂ by a corresponding virtual tunnel interface (VTI) 250 ₁-250 ₂ and a state of each of the IPSec tunnel 137 ₁₁-137 ₁₂ may be represented by a corresponding virtual tunnel interface (VTI) state 260 ₁-260 ₂. The VTI state 260 ₁-260 ₂ and with the ECMP metrics 270 ₁-270 ₂ are used to control selection in the use of IPSec tunnels 137 ₁₁-137 ₁₂ given whether these IPSec tunnels 137 ₁₁-137 ₁₂ are active or disabled.

Additionally, the full-mesh network 110 provides another technological advantage by establishing more reliable communications by configuring each of the gateways 125 ₁-125 _(M) and 135 ₁-135 _(N) with secondary tunnels to support data traffic when all IPSEC tunnels for a particular gateway have failed. As an illustrative example, as shown in FIG. 1 , the first spoke gateway 125 ₁ deployed within the spoke VPC 120 establishes a secondary tunnel 1291 with the second spoke gateway 125 ₂. According to one embodiment of the disclosure, each of the secondary tunnels (e.g., secondary tunnel 1291) may be configured in accordance with Generic Routing Encapsulation (GRE) tunnel protocol to secure communications between the spoke gateways 125 ₁-125 ₂ within the spoke VPC 120 and the transit gateways 135 ₁-135 ₂ within the transit VPC 130. However, it is contemplated that another tunneling protocol, such as any IP routable tunnel reliance on Private IP addressing) may be used other than GRE.

Herein, the GRE tunnel formation among the spoke gateways 125 ₁-125 _(M) (M≥2) within the spoke VPC 120 is described in detail, give the GRE tunnel formation for the transit gateways 135 ₁-135 _(N) within the transit VPC 130 is consistent. In general, the spoke gateways 125 ₁-125 _(M) are configured with GRE tunnels towards all other gateways in the spoke VPC 120, where the GRE tunnels may be maintained within the gateway routing tables 170 ₁-170 _(M) and terminated by VTIs associated with the corresponding gateways. For this embodiment, for the spoke VPC 120, the first spoke gateway 125 ₁ would be configured with “M−1” backup GRE tunnels such as GRE tunnel 12912 established between the first spoke gateway 125 ₁ and the second spoke gateway 125 ₂. Similarly, “M−2” GRE tunnels may be established between the second spoke gateway 125 ₂ and any of the remaining gateways 125 ₃-125 _(M) within the spoke VPC 120. As shown, the first spoke gateway 125 ₁ is configured with GRE tunnel 129 ₁₂, which establishes secondary communications with the second spoke gateway 125 ₂.

The GRE tunnels may be programmed with different ECMP metrics to designate an order of selection in case any GRE tunnels fail due to failure of the assigned gateway itself. Also, the ECMP metrics associated with the GRE tunnels are set with a higher ECMP metric than ECMP metrics associated with any of the IPSec tunnels so that the GRE routing is selected if routing via any IPSec tunnel is not available. Hence, as shown, none of the gateways 125 ₁-125 ₂ will forward data traffic via the GRE tunnels 129 ₁₂ until all IPSEC tunnels towards remote peers are down (disabled).

Referring still to FIG. 1 , each of the on-prem computing devices 180 ₁ and 180 ₂ operates as a network router by propagating data traffic (e.g., one or more messages) originating from one of the cloud instances 140 through multiple VPCs forming the full-mesh network 110. Upon receipt of the message(s), using a local routing table, the targeted on-prem computing device (e.g., device 180 ₁) forwards the message(s) to the destination instance(s).

Referring to FIG. 3 , an exemplary illustration of a logical representation of a gateway 300 (e.g., first spoke gateway 125 ₁) deployed in a virtual private cloud network of FIG. 1 is shown. In one embodiment, the gateway 300 may correspond to logic that provides a logical connection between a source 310 and a destination 320. For example, the source 310 may correspond to a user (on-prem computing device), resource within a VPC (e.g., cloud instance), or another gateway that supports connectivity with the destination 320, as referenced by a first VTI 315. Herein, in this example, the destination 320 may correspond to a cloud instance (when the source 310 is a user or gateway), a user (when the source 310 is a cloud interface or a gateway), or a gateway (when the source 310 is a user, cloud interface or another gateway), as referenced by a second VTI 325. As represented, the gateway 300 may support logical connections with one or more sources 310 and/or one or more destinations 320.

The gateway 300 may be configured with routing logic 350 and a data store 360. As shown in FIG. 3 , the data store 360 may include a gateway routing table 370 (e.g., gateway routing table 170 ₁ where the gateway 300 corresponds to the first spoke gateway 125 ₁) and a route database 380. The gateway routing table 370 is referenced by the routing logic 350 in determining which communication link is used for transmission of the data received from the source 310 for routing towards the destination 320. The routing database 380 is configured to retain routing paths 390 for retrieval when a disabled routing path is removed from the gateway routing table 370.

As an optional component, the gateway 300 may include NAT logic 395 which, when executed, is configured to perform translation of the IP addresses for data packets transmitted between the spoke VPC 120 and the transit VPC 130. For example, in the Internet gateway 300, the NAT logic 395 may create a destination NAT entry to translate a private IP address associated with the source 310 residing within the spoke VPC 120 to a private IP address utilized by the transit VPC 130 in which the destination 320 is located. Similarly, an inverse translation is conducted where the private IP address associated with the transit VPC 130 may be returned back into the private IP address associated with the spoke VPC 120.

Referring now to FIG. 4 , a second exemplary embodiment of a multi-cloud computing platform 400, including the full-mesh network 110 configured to mitigate the disruption of communications between a plurality of VPCs 410, 420, 430 and 440, is shown. The first VPC 410 includes a first set of spoke gateways 415 operating within a selected geographic region supported by a first public cloud network 402 (e.g., Amazon® Web Services “AWS”). The second VPC 420 includes a second set of spoke gateways 420, where these spoke gateways 420 may correspond to logic, sometimes referred to as “virtual networks” (VNets). The second set of spoke gateways (Vnets) 420 operates within the same or a different geographic region as the first VPC 410 and is deployed within a second public cloud network 404 (e.g., Microsoft® Azure®) different than the first public cloud network 402.

Additionally, as shown in FIG. 4 , the third VPC 430 includes a first set of transit gateways 435 operating within the first public cloud network and the fourth VPC 440 includes a second set of transit gateways 445. The second set of transit gateways 445 may correspond to VNets operating within the Microsoft® Azure® cloud network being the second public cloud network 404. Stated generally, the second cloud network 404 corresponds to any public cloud network different than the first public cloud network 402 (e.g., Google® Cloud, Microsoft® Azure®, etc. when the first public cloud network 402 is AWS) and the second set of transit gateways 445 constitutes any type of resources that effectuate data transfer with the first set of transit gateways 435.

Similar in architecture of the multi-cloud computing platform 100 described in FIG. 1 , each spoke gateway of the first set spoke gateways 415 is communicatively coupled to each transit gateway of the first set of transit gateways 435 through IPSec tunnels 450 ₁₁, 450 ₁₂, 450 ₂₁, 450 ₂₂, 450 ₃₁ and 450 ₃₂ in a crisscross scheme. Additionally, each of the spoke gateways 415 is communicatively coupled together via GRE tunnels 455 ₁-455 ₃.

As further shown in FIG. 4 , each transit gateway of the first set of transit gateways 435 is communicatively coupled to each spoke gateway of the first set of spoke gateways 415 through IPSec tunnels 450 ₁₁-450 ₃₂ as described above. Additionally, each of the first set of transit gateways 435 deployed within the third VPC 430 is communicatively coupled to (i) the on-prem computing devices 180 within the on-premises network 190 (e.g., on-prem computing devices 180 ₁ and 180 ₂) via IPSec tunnels 460 ₁₁, 460 ₁₂, 460 ₂₁ and 460 ₂₂ and (ii) each transit gateway of the second set of transit gateways 445 deployed within the fourth VPC 440 being part of the second public cloud network 404 via IPSec tunnels 470 ₁₁, 470 ₁₂, 470 ₂₁ and 470 ₂₂. The second set of transit gateways 445 is communicatively coupled to the second set of spoke gateways 425 (e.g., corresponding to spoke VNets for Microsoft® Azure® deployment) via IPSec tunnels 480 ₁₁, 480 ₁₂, 480 ₂₁ and 480 ₂₂.

As further shown in FIG. 4 , each of the gateways with the VPCs may be communicatively coupled together via GRE tunnels to avoid VPC routing table reprogramming upon failure of IPSec tunnels associated with a particular gateway. In particular, each of the first set of spoke gateways 415 is communicatively coupled together via GRE tunnels 455 ₁-455 ₃. Similarly, each of the first set of transit gateways 435 is communicatively coupled together via GRE tunnel 465 while each of the second set of spoke gateways 435 and the second set of transit gateways 445 is communicatively coupled together via GRE tunnel 475 and GRE tunnels 485, respectively.

It is contemplated that two or more of the VPCs 410, 420, 430 and 445 may reside in different public cloud networks. For instance, according to one embodiment of the disclosure, each of the VPCs 410, 420, 430 and 445 may be deployed in a different public cloud network than any of the other VPCs. According to another embodiment of the disclosure, at least two of the VPCs 410, 420, 430 and 445 may be deployed within one type of public cloud network and at least one of the remaining VPCs 410, 420, 430 and 445 may be deployed within another type of public cloud network.

The communications between the second VPC 420 and the fourth VPC 440 provide a reliable communication scheme among multiple VPCs featuring spoke gateways that enable a user to access cloud instances with the first VPC 410 via the first set of spoke gateways 415 and the second VPC 420 via the second set of spoke gateways 425. Also, when multiple VPCs are deployed and support inter-communications, this spoke-hub architect has advantage over full meshed direct peering between VPCs—it is more cost effective (e.g., less peering connections needed; lower requirement for VPC gateway resources, etc.), easier manageability, and the like.

III. Operational Flow

Referring now to FIG. 5 , a flowchart of an exemplary embodiment of the operability of the public cloud computing platform of FIG. 1 in supporting communications between multiple virtual private cloud networks (VPCs) that are designed to mitigate the necessity of reprogramming VPC routing table(s) based on communication link failures experienced by gateways within the VPC. Herein, according to one embodiment of the disclosure, the controller collects VPC information as described above (block 500). Thereafter, for the public cloud computing platform illustrated in FIG. 1 for example, the controller configures a first VPC routing table to identify (i) which instance subnet maintained within the first (spoke) VPC corresponds to which gateway and (ii) which gateways of the first VPC are in communication with which gateways of the second (transit) VPC (block 510).

Additionally, the controller may initially configure each of the gateway routing tables to create mesh-style, peer-to-peer communication links between remote gateways such as spoke-transit gateways implemented on different VPCs (e.g., IPSec tunnels) as well as communications between transit gateways and computing devices (e.g., routers) of the on-premises network (block 520). For load balancing, each of the communication links, represented as routing paths, may be configured with multi-path (ECMP) routing parameters (e.g., identical routing weights and ECMP metrics) to ensure that sources may rely on the routing paths equally. Additionally, these gateway routing tables may include peer-to-peer communications (secondary tunnels) between spoke gateways or transit gateways within the same VPC (block 530). As a result, the VPC routing table and gateway routing tables specific to each gateway are generated, where the gateway routing tables are now responsible for alternating its gateway routing table to address state channels within the IPSec tunnels and GRE tunnels.

In response to a communication path failure, such as an IPSec tunnel becomes disabled for example, the spoke or transit gateway associated with the failed IPSec tunnel disables the communication link (routing path) by altering the VTI state within an entry associated with the disabled IPSec tunnel (blocks 540 and 550; FIGS. 6A-6B). Thereafter, the gateway determines whether all IPSec tunnels from the gateway directed to next hop have become disabled (block 560). If not, a different IPSec tunnel available to the gateway is used (block 565). If so, the gateway utilizes the secondary tunnel as a route for data traffic to the next hop via another gateway (block 570; FIG. 6C). This process continues until one of the IPSec tunnels returns to an active state. In the meantime, the gateways monitor whether the failed IPSec tunnel is returned to “active” status (block 580). If so, the gateway recovers the failed IPSec tunnel by returning the IPSec tunnel to the gateway routing table upon returning the VTI state to “active” status and gracefully discontinuing routing over the secondary tunnel (block 590), where IPSec tunnel status is continued to be monitored.

Embodiments of the invention may be embodied in other specific forms without departing from the spirit of the present disclosure. The described embodiments are to be considered in all respects only as illustrative, not restrictive. The scope of the embodiments is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope. 

What is claimed is:
 1. A network system comprising: a first virtual private cloud network including a first plurality of gateways, the first virtual private cloud network being deployed within a first public cloud network; a second virtual private cloud network including a second plurality of gateways, the second virtual private cloud network being deployed within a second public cloud network different than the first public cloud network, each of the second plurality of gateways being communicatively coupled to each of the first plurality of gateways over cryptographically secure tunnels; and a controller configured to control operability of the first virtual private cloud network and the second virtual private cloud network, the controller to access routing tables being non-transitory storage medium assigned to gateways associated with the first virtual private cloud network and the second virtual private cloud network, wherein responsive to a cryptographically secure tunnel of the cryptographically secure tunnels failing, a gateway of the first plurality of gateways updates a gateway routing table autonomously by altering information within an entry within the gateway routing table associated with the failed cryptographically secure tunnel without reliance on activity by the controller that manages operability of a full-mesh network including the cryptographically secure tunnels.
 2. The network system of claim 1, wherein each gateway of the first plurality of gateways is in communication with one or more other gateways of the first plurality of gateways over one or more cryptographically secure tunnels and a first gateway of the first plurality of gateways is in communication with at least a second gateway of the first plurality of gateways over a cryptographically secure tunnel of the one or more cryptographically secure tunnels operating in accordance with a tunneling protocol to secure communications between each of the first plurality of gateways for subsequent communication to one of the second plurality of gateways.
 3. The network system of claim 2, wherein each of the first plurality of gateways and the second plurality of gateways correspond to a virtual machine (VM)-based data routing component, each of the first plurality of gateways is assigned a Private Internet Protocol (IP) address within an IP address range associated with the first virtual private cloud network and each of the second plurality of gateways is assigned a Private IP address within an IP address range associated with the second virtual private cloud network different than the first virtual private cloud network.
 4. The network system of claim 2, wherein the cryptographically secure tunnel of the one or more cryptographically secure tunnels is active when no cryptographically secure tunnels communicatively coupled to the first gateway of the first plurality of gateways is active.
 5. The network system of claim 1, wherein the cryptographically secure tunnels operate in accordance with an Internet Protocol Security (IPSec) protocol.
 6. The network system of claim 1, wherein each of the cryptographically secure tunnels is set to identical, equal cost multi-path (ECMP) routing metrics to achieve load-balancing.
 7. The network system of claim 6, wherein each of the one or more cryptographically secure tunnels is assigned a lower ECMP routing metric than any ECMP routing metric assigned to a cryptographically secure tunnel of the cryptographically secure tunnels.
 8. The network system of claim 1, wherein each of the cryptographically secure tunnels is assigned a different routing weight to achieve load-balancing, the weight being based on bandwidth capacity.
 9. The network system of claim 1, wherein the first plurality of gateways operate as transit gateways deployed within a first region of the first public cloud network and the second plurality of gateways operate as transit gateways deployed within a second region of the second public cloud network.
 10. The network system of claim 1, further comprising a third virtual private cloud network including a plurality of spoke gateways, each of the plurality of spoke gateways being communicatively coupled to each of the first plurality of gateways via cryptographically secure tunnels, the third virtual private cloud network being deployed within the first public cloud network.
 11. The network system of claim 1, further comprising a third virtual private cloud network including a plurality of spoke gateways, each of the plurality of spoke gateways being communicatively coupled to each of the first plurality of gateways via cryptographically secure tunnels, the third virtual private cloud network being deployed within the second public cloud network or a public cloud network different than the first public cloud network.
 12. The network system of claim 1, wherein responsive to a cryptographically secure tunnel of the cryptographically secure tunnels becoming operational, a gateway of the first plurality of gateways updates the gateway routing table autonomously by altering information within an entry within the gateway routing table associated with the cryptographically secure tunnel that has become operational without reliance on activity by the controller.
 13. A method for supporting the transmission of data between multiple public cloud networks, comprising: selecting a first transit gateway by a first resource of a first public cloud network to receive data directed to a second resource deployed within a second public cloud network different than the first public cloud network, the first and second public cloud networks being communicatively coupled over cryptographically secure tunnels to enable communications between the first and second resources; receiving the data by the first transit gateway deployed within the first public cloud network; transmitting the received data from the first transit gateway to a second transit gateway deployed within the second public cloud network over the cryptographically secure tunnel; routing the received data from the second transit gateway to the second resource; and responsive to a cryptographically secure tunnel of the cryptographically secure tunnels between the first and second public cloud networks failing, a gateway of the first public cloud network updates a gateway routing table autonomously by altering information within an entry within the gateway routing table associated with the failed cryptographically secure tunnel without reliance on activity by the controller.
 14. The method of claim 13, wherein the cryptographically secure tunnels are configured in accordance with an Internet Protocol Security (IPSec) protocol.
 15. The method of claim 13, wherein the first resource constitutes a spoke gateway of a first private virtual network deployed within the first public cloud network corresponding to an Amazon Web Services cloud network.
 16. The method of claim 15, wherein the second resource constitutes a virtual network of a second private virtual network deployed within the second public cloud network corresponding to a Microsoft Azure cloud network.
 17. The method of claim 13, wherein responsive to a cryptographically secure tunnel of the cryptographically secure tunnels becoming operational, a gateway of the first plurality of gateways updates the gateway routing table autonomously by altering information within an entry within the gateway routing table associated with the cryptographically secure tunnel that has become operational without reliance on activity by the controller. 